Generally, streetlamp devices are lighting fixtures installed along the street to provide safety and security in road traffic. Such streetlamp devices are installed on main roads, roads in business zones and residential zones in suitable forms depending on places thereof. According to the present installation standards of streetlamp devices, when installing streetlamp devices 10 meters above the ground, side illumination occurring in locations 12 meters from right and left sides of a place on the ground, where the streetlamp device is installed, should be 20 lux.
Conventional streetlamp devices employ lamps emitting light using the resistance of filaments, which have short lifespans and consume a lot of power. Recently, there have been developed and applied light emitting diode streetlamp devices employing LED lamps as light sources, the LED lamps having lifespans longer than those of the lamps employing filaments, the efficiency of the LED lamps being high.
On the other hand, as shown in FIG. 1, a general LED streetlamp device 100 includes a body frame 130 with LED lamps 110 attached as light sources and a reflective plate 120 reflecting light from the LED lamps 110 toward an area directly below or a peripheral area; and a transmission plate 140 manufactured using transparent glass or transparent plastic covering the LED lamps 110 and the reflective plate 120 attached to the body frame 130. Also, on top of the body frame 130, there is provided a fastening portion 150 formed in the shape of a bar or a pipe. Accordingly, the LED streetlamp device 100 may be attached and installed to a connecting bar 210 of a lamppost 200 by coupling the fastening portion 150 therewith using a general coupling member 220 formed of one of a bolt, a nut, and a bracket.
Also, the connecting bar 210 of the lamppost 200, coupled with the fastening portion 150, is formed in the shape of a bar with a certain diameter. However, in some cases, as an example, when providing a shielding member 230 for protecting the streetlamp device 100 together with the connecting bar 210 formed in a single body, as shown in FIG. 2, the connecting bar 210 may have an extended diameter of an end thereof. In this case, the fastening portion 150 of the LED streetlamp device 100 is also designed according to the extended diameter of the connecting bar 210.
Referring to FIG. 2, a reference numeral 210a indicates an extended diameter portion of the connecting bar 210 and a reference numeral 150a indicates an extended diameter portion of the fastening portion 150. Also, in FIG. 2, for example, the extended diameter portion 150a of the fastening portion 150 is coupled with the extended diameter portion 210a of the connecting bar 210 by a screw-connection.
However, considering that streetlamp devices are generally deployed with intervals about 30 to 50 meters apart along the street, the LED streetlamp devices 100 should emit light to the front and rear of the street to provide 20 lux of illumination on a spot on the ground 12 meters from the front and rear of a location on the street, which is the standard for installing streetlamp devices.
However, since the LED streetlamp device 100 only has one of a flat configuration and a configuration inclined toward a certain direction and emits light only toward the area directly below and a certain position of the peripheral area, it is not possible to uniformly emit light toward the area directly below and the peripheral area.
Also, since the LED streetlamp device 100 emits heat of a high temperature due to characteristics thereof, there may occur damage to diodes due to the heat. However, there is no effective countermeasure against the heat emission of the body frame 130.
Also, there is a problem in that it is not easy to install the lamp on the lamppost. That is, it is necessary to prepare streetlamp devices having diameter portions suitable for the diameter of the connecting bar.
Also, in case of the streetlamp device 100, since the light from the light sources 110 passes through the transmission plate 140, the strength thereof is decreased due to reflection or scattering.